1. Field of the Invention
The field of the invention relates to valves which are adapted to control the flow of radioactive slurries passing through welded pipelines, wherein the valves are located in relatively inaccessible locations, in underground sumps, in pits or under water. Since the media is radioactive and the location of the valves is relatively inaccessible, it is important that the valve, per se, be easily replaced.
2. Description of the Prior Art
U.S. Pat. No. 3,809,114 dated May 7, 1974, to J. W. Mueller, et al, discloses an underground valve the body of which is secured to underground inlet and outlet pipes by bolted flanges. The valve plug 14, which is rotatably by its stem 17 which is secured to shaft 30, includes lifting pins 21 which engage slots in the lower ends of a pair of diametrically disposed slip members 20, 20. When bonnet 28 which is bolted to the upper end of a tubular extension 33 which extends upwardly from the valve body, is removed, the shaft 30, stem 17, valve plug 14, slip members 20, top plate 18 and hold down sleeve 39 are released for withdrawal, upwardly, through extension 33. The valve body remains underground bolted to the pipes through which the media being controlled passes.
U.S. Pat. No. 3,081,792 dated Mar. 19, 1963, to G. E. Hansen discloses a Ball Valve with Removable Cartridge Unit wherein a spherical valving member is rotatably journaled within a hollow valve plug or cage of frusto-conical configuration which tapers from a maximum lower diameter to a lesser upper diameter, said cage being snuggly fitted within a complimentary, tapered bore within valve body 1. The cage is secured in place with respect to the body member by means of a thrust washer 56 which exerts a continuous upward pull to the casing for securing it to and in the valve body. The operating stem for the ball extends upwardly from the valve plug or cage thereby precluding removal of the valving elements of the device absent free access to both the upper and lower portions of the valve body.
U.S. Pat. No. 3,179,121 dated Apr. 20, 1965 to K. B. Bredtschneider et al discloses a Removable Head and Seat Unit Ball Valve Construction wherein a spherodial closure member and its respective valve seats may be removed as a unit from the valve body.
Applicants are likewise aware of the following U.S. patents:
U.S. Pat. No. 2,997,057 dated Aug. 22, 1961 to L. R. Toth PA1 U.S. Pat. No. 3,100,501 dated Aug. 13, 1963 to G. E. Hansen, et al PA1 U.S. Pat. No. 3,132,836 dated May 12, 1964 to J. L. Dickerson, et al PA1 U.S. Pat. No. 3,150,681 dated Sept. 29, 1964 to G. E. Hansen, et al PA1 U.S. Pat. No. 3,186,680 dated June 1, 1965 to E. P. Pool PA1 U.S. Pat. No. 3,362,433 dated Jan. 9, 1968 to I. J. Heinen PA1 U.S. Pat. No. 3,450,384 dated June 17, 1969 to J. D. Watts PA1 U.S. Pat. No. 3,522,820 dated Aug. 4, 1970 to J. D. Watts